Embossing devices from the prior art having rolls are predominantly used for embossing packaging foils, for example for the foodstuffs industry, the pharmaceutical industry and in particular for the tobacco goods industry. In the tobacco goods industry, devices having embossing rolls have been used for more than 30 years for embossing packaging foils, in particular so-called innerliners, these innerliners not only being provided with decorative effects but also with authentication features. Here, the paper component is stabilized in such a way that the foil can be processed without inconvenience in the following packaging plant.
However, in the tobacco goods industry, it is not just packaging foils that are processed or embossed but also the paper and the mouthpiece, also called tipping, for encasing the individual cigarette. During the processing of cigarette paper and of the mouthpiece, in addition to the decorative effect, endeavors are primarily made to make perforations deliberately in the cigarette paper and in the mouthpiece, in order to increase the throughput of air during smoking.
As opposed to the increased throughput of air of a cigarette during drawing, in various states, including in the EU, statutory regulations have been granted or are being prepared to the effect that the cigarettes, when not being smoked, will extinguish themselves after a specific time interval. This is achieved by means of a fire-retardant substance which initially was applied in the LIP zones and which, for example, can consist of a coating in the interior of the cigarette paper, in order to reduce the porosity. In recent times, it has transpired that this zonal coating is too complicated for mass production and the trend to providing the entire cigarette paper with the fire-retardant substance before the processing has therefore become widespread. The result of this is that perforations become necessary in order to achieve the necessary throughput of air. However, the perforations cannot extend randomly over the length of the cigarette but must be arranged at specific points.
Most of the devices known at present for producing perforations in cigarette paper are implemented by means of a laser system since, in principle, the quantity and size of holes can be set well thereby. Such laser systems for producing relatively large holes are very complicated, however, and cannot be used online in a cigarette production machine.
Within the content of the present invention, the term tobacco goods production machine is understood to mean equipment for encasing individual tobacco goods items such as cigarettes, this machine being designated a “maker” in this application. Here, the embossed foil can be fed to the maker directly or indirectly by a robot. Both methods are designated online methods. From there, the cigarettes pass to a tobacco goods packaging machine, also called a “packer” for short, in which a number of cigarettes are packed. In the present application, only the maker following the perforation is of interest.
In the case in which porous cigarette paper is used to increase the draw during smoking, the area in which the cigarette paper is porous can be embossed in such a way that the cigarette paper becomes corrugated at this point, so that when this cigarette paper is encased with the mouthpiece paper, additional air-conducting areas are produced, which increase the quantity of air during drawing. Examples of such perforation systems are disclosed in U.S. Pat. No. 3,596,663, EP 0 536 407 A1 and GB 2 133 269 A.
It is also known, for example from WO 2011/131529 A1, to apply perforations by means of embossing rolls, it being possible for the perforations to be applied only at specific points, for example outside the LIP zones which effect the extinguishing of the cigarette after a certain time. In this WO application, it is primarily emphasized that the film must not be weakened by the perforations in such a way that, during the further processing, tearing of the same can be caused. For the perforations, the teeth, which have been known per se for a long time, are used in a pin-up pattern, the teeth being disclosed as pyramidal. The WO application likewise discloses a monitoring unit which examines the foil following the embossing, in order to determine various properties of the embossed foil and, with regard to the tearing resistance, in order to control the mutual pressure of the embossing rolls and therefore the penetration depth of the teeth into the paper.